Hi All – I’m editing this post on 9/1/16 to add the technical data on the dredger; the cost savings; and the oversight as supplied by Dan Fredricks, project engineer – I’ll just copy it here in *bold*, since I’m not able to make it a different color or font to let you know where the changes were made:
We appreciate your concerns and want to assure everyone that we have assembled an experienced and qualified team to complete the channel dredging along the Cuddy Intercounty Drain and Island Drive Channel.
In regard to Mr. Bidol’s concern about the type of dredging equipment being used, we are using mechanical (as opposed to hydraulic) excavating equipment; however, the equipment is every bit as modern and precise as hydraulic dredging methods. The dredging Contractor, GroAmerica, is equipped with the latest electronic technology installed on their mechanical dredging equipment. The dredger that will be used on the Cuddy / Island Drive channels is equipped with 2015 Topcon GPS system that is controlled using 3 fixed points to provide a real-time 3D image of channel bottom. This allows the Contractor to precisely monitor what is being dredged. GroAmerica owns both hydraulic and mechanical equipment; however, they chose to use a mechanical excavator because it will allow them better access to tight spaces near docks and boat houses to provide the best possible finished product. In addition, the cost savings of using mechanical versus hydraulic dredging equipment saved residents almost $45,000.
In addition to the Contractor’s quality control provisions, Land and Resources Engineering will have a full time inspector on-site that will be routinely checking GroAmerica’s work. Should residents have any questions or concerns during construction, please feel free to contact our office and we will do our best to address their needs.
OK – back to my original post and a giant “thank you” to Dan for the info!
Last night’s cruise up and down the Cuddy and Island Dr channels was informative, and there have been some changes to the dredging plan that residents need to know, so spread the word!!
#1. The dredging will be done mechanically*, with a doublewide barge and long-reach excavator. This is good because it saves us money (I thought I heard Dan say it saved
$82,000? $45,000); this is temporarily bad for the slackers, because the working barge is 40′ x 40′. There’s not much chance that you’ll be able to navigate past that when they’re working. GET YOUR BOATS AND BOAT LIFTS OUT BEFORE SEP’T 12TH!!!!
#2. The starting point will be the Bayview Marina. There will also be 2 “hauling barges” that deliver the dredged sediment to the marina boat ramp. From there, the sediment will be dumped into trucks and taken to a site where it will be used for “land reclamation” by a gravel mine. There was some discussion as to the path the dredger will take (upstream, downstream, or Island Dr channel?) and I think that will be determined by how the bridge reconstruction is going. Everyone involved recognizes that there’s no sense in dredging upstream until the risk of sediment being released by land construction is passed.
#3. Three projects will run concurrently: dredging, bridge replacement, and reopening the Sedimentation Basin** and adding the Debris Barrier. There is still upstream remediation on the west side of Patterson that needs to take place (like replacing the culverts under Timber Creek and stabilizing some stream banks) – but Dan Fredricks said that those might wait until Spring when the grass used to stabilize the banks will grow. If they leave large bare spots over the winter, those could erode and cause the very problems they were trying to fix. The Basin will catch any sediment caused by upstream work.
#4. After Labor Day, Dan Fredricks (project engineer) and Jim Rosendall (dredger) will take videos of all the property frontage along the Cuddy and Island channels. On our “cruise”, we noticed some seawalls, docks, and boat houses, that look like they are unstable. A few look like they’re one good breeze from falling over….. the dredger will be taking great care when working around anyone’s seawalls and docks; but particularly when working around the “shaky” ones. The video protects the dredger against those who might hope to gain a new seawall for free.
#5. The good news: there were remarkably few hindrances to dredging, assuming all the boats and boat lifts are out of the way (a few folks have already removed their boats and lifts!). The residents we talked to about their frontage, seemed more than willing to move some small docks out of the way to get better water depth. Most of the permanent decks/docks posed no particular problem, and Jim felt he could at least get a swipe out of the cut-in “boat bays”.
*Jim explained how mechanical dredging is done: since they can’t see the bottom blade of the bucket, they watch a monitor screen that turns red when the bucket has reached the designated depth. He will be dredging the deepest part a little wider than proposed; then the sides will be “stepped” up, in order to have a 2′ water depth at the seawall. He said by removing the sediment by bucket, it’s quite “dry” (as opposed to hydraulic dredging that needs lots of water to move the sediment) – and the trucks that will carry away the sediment shouldn’t leak. He said they recently did a job that removed 45,000 cubic yards (I think we’re removing 17,000 cu yds from the Cuddy), and didn’t received one complaint about mud/dust, etc.
I asked Jim how far they can travel in a day – he said about 4 houses, assuming 100′ frontage.
Something I just thought of: this process should be quieter (relatively speaking) than hydraulic dredging? I can only imagine how constantly loud the pumps would be, that could move sediment a mile upstream??
**Yes, we leased almost 5 acres for the dredging spoils to be deposited on – now the plan is to use the temporary-lease land for sediment removed in reopening the Basin; and reserving the permanently-leased land for Basin maintenance.